Oral Roberts, a dirt-poor Oklahoma farm boy who popularized the idea of a "prosperity gospel" while becoming one of the world's most recognizable televangelists, died Tuesday. He was 91.

Roberts, founder of the university in Tulsa, Okla., that is named after him, died from complications of pneumonia at a Newport Beach hospital, family spokeswoman Melany Ethridge said. He had suffered a fall over the weekend.

Roberts pioneered the use of television and computerized databases to spread the Gospel and raise hundreds of millions of dollars -- a formula followed today by numerous other ministries.

Using sophisticated and relentless direct-mail campaigns, Roberts asserted that God generously rewarded financial acts of faith performed in God's name. This credo became known as the "prosperity gospel."

"It gives people hope and expectation that seeds sown to God will be multiplied back in every area of life," Roberts wrote in his 1995 autobiography, "Expect a Miracle: My Life and Ministry."

Roberts brought Pentecostalism -- which promotes charismatic worship including faith healings and talking in tongues -- to the American mainstream, giving it a newfound sense of legitimacy among the middle class and within other denominations.

"More than any other person, he should be credited with starting the charismatic movement in mainline religion," said Vinson Synan, dean of the divinity school at Regent University in Virginia and a historian of the Pentecostal movement. "He brought [divine] healing into the American consciousness."

Worldwide, the charismatic branch of Christianity -- now found in mainstream denominations as well as Pentecostalism -- grew from an estimated 20 million to 600 million during Roberts' seven decades of ministry. His international broadcasts and crusades deserve a large part of the credit for the increase, Christian scholars said.

"With the passing of Oral Roberts the world has lost one of the most inspiring voices for Christ of this century," Robert H. Schuller, founding pastor of the Crystal Cathedral in Garden Grove, said in a statement. "Twentieth century history of Christianity will name Oral Roberts as the voice that brought the Pentecostal movement to be taken seriously by mainline Christianity."

In the 1970s, Roberts' prime-time TV specials drew 40 million viewers, and he appeared frequently on talk shows hosted by Johnny Carson, Dinah Shore and Merv Griffin. The preacher also had a half-hour program -- "Something Good Is Going to Happen to You" -- that aired Sundays.

By 1980, Roberts was recognized by 84% of Americans, close behind the sitting U.S. president and fellow evangelist Billy Graham and 40 points ahead of the next religious figure.

"Not bad," he once said, "for a poor boy with a speech impediment who was supposed to die of tuberculosis before he was 20."

At the time of his death, however, Roberts' ministry and celebrity had been in decline for years, a drop-off accelerated by a prophecy the preacher made 22 years ago that "God will call me home" unless $8 million was raised for scholarships to Oral Roberts University by March 31, 1987.

The money was raised, but by then Roberts had become a figure of ridicule to many inside and outside the Christian world.

With dwindling revenues -- they once stood at more than $100 million a year -- the televangelist was forced in 1989 to downsize his ministry, laying off 250 employees, closing Tulsa's City of Faith medical center and an adjoining medical school, and selling vacation homes and luxury cars to raise money.

A heart attack in 1992 forced him into semi-retirement, though he remained the chancellor of the university. He spent most of his final years in a Newport Beach condominium with his wife, Evelyn, who died in April 2005. They had been married 66 years.

Humble beginnings

Granville Oral Roberts, the youngest of five children, was born in a log cabin near Ada, Okla., on Jan. 24, 1918, the son of a part-time preacher and farmer. His mother was part Cherokee.

Roberts was raised in a Pentecostal-flavored Methodist church, and the family later joined the Pentecostal Holiness Church.

He contracted tuberculosis as a teenager and spent five months bedridden before his family took him on a mattress to a healing service at a tent revival. It was there, Roberts reported in his autobiography, that he was healed of TB and his stutter and that he first heard God's plan for his life: "Son, I am going to heal you, and you are to take my healing power to your generation. You are to build me a university and build it on my authority and the Holy Spirit."

In 1936, the 18-year-old Roberts began preaching at revivals as a minister for the Pentecostal Holiness Church. Two years later, he married Evelyn Lutman, a union that produced two sons and two daughters.

For nearly a decade, Roberts pastored several Oklahoma churches and preached at revivals while attending college. Then, he said, God spoke to him again, telling him not to be like other men but to "heal the people as He did." Roberts said he could feel the power to heal by the tingling of his right hand.

His first healing service drew 1,200 people, and a few weeks later a healing revival in Tulsa attracted enough people to be extended for nine weeks.

Anecdotal evidence of Roberts' reputed healings made news as many of his followers claimed their ailments had disappeared during a revival. At his first healing service, a German woman reportedly said her right hand, crippled for 38 years, had been restored. Another evening, a blind man is said to have shouted, "I can see! I can see!"

During his ministry, no scientific studies confirmed the evangelist's ability to heal.

Roberts soon began filling up stadiums or huge tents with as many as 25,000 believers.

In a pattern that would continue over the years, his healing ministry was attacked by the media, skeptics and mainstream denominations.

In 1950, Roberts took a big step toward the mainstream of American Christianity when he was invited to say the opening prayer at a Billy Graham crusade after a chance meeting of the preachers at a hotel in Portland, Ore.

"Graham's personal kindness, his glad and wholesome embrace of a fellow Christian, placed Oral momentarily in a larger, more respectable, world than he had ever imagined he could be a part of," according to the 1985 biography "Oral Roberts: An American Life" by David Edwin Harrell Jr.

The preachers remained cordial over the years, though Roberts could never match the good press that Graham received.

Roberts came in for criticism in the 1950s when, occasionally, a worshiper would die during a crusade. Ministry spokesmen said the deaths were not unusual considering how many sick people were in attendance.

The minister was controversial for other reasons as well. In the days of segregation, Roberts, like Graham, insisted that black and white worshipers sit together, a progressive policy he said brought him death threats.

"We didn't think of being ahead of our time," Roberts recalled.

In 1954, Roberts became one of the first televangelists, taping his crusades and then airing them on TV stations across the nation. Within a year, his programs were being carried by more than 200 stations.

At the end of each show, Roberts didn't ask for money but told viewers to send a letter to Oral Roberts, Tulsa, Okla.

One of the challenges of his booming enterprise was how to handle the thousands of letters that poured in each week. Again a trailblazer, he worked with IBM to develop one of the first computerized systems to immediately send out seemingly personalized letters.

Among the projects he financed this way was what was initially called the Oral Roberts University of Evangelism. His original idea was to train foreign students to spread the Gospel throughout the world. That evolved into a vision of a full-scale university that would combine Bible teaching with academic and athletic programs.

Oral Roberts University opened in 1965 with 300 freshmen, and in 1971 the 263-acre college was accredited.

Changing denominations

As the end of the 1960s approached, Roberts' crusades drew dwindling numbers. A final blow came in 1968, when Roberts shocked his followers -- and the Pentecostal Holiness Church, sponsor of his events -- by becoming a Methodist minister.

His shift to the Methodists allowed him more leeway in mixing secular elements like dancing into his television shows and represented another move toward the mainstream and a larger flock to lead.

Roberts ended his crusades and his long-running television show in 1968. The following year, he launched one-hour prime-time specials centered around celebrities such as Pat Boone, Dale Evans, Anita Bryant, Robert Goulet, and Johnny and June Carter Cash.

Although many of Roberts' longtime supporters were appalled by what they saw as the secularization of Christianity, within three years nearly 40 million viewers were tuning in to the prime-time specials and they, along with his weekly Sunday show, generated 760,000 letters a month -- a gold mine of potential donors who were added to Roberts' increasingly sophisticated direct-mail database.

By this time, he had abandoned the flashy suits of his tent revival days in favor of tailored clothes.

In 1970, he published "The Miracle of Seed-Faith," which promised financial riches for those who gave to God -- which he called planting a seed of faith.

In 1975, Roberts announced plans for the university to build medical, dental and law schools. The annual budget for Oral Roberts Evangelical Assn. -- his umbrella organization -- approached $40 million.

But the first of a series of family tragedies struck in 1977 when Roberts' 37-year-old daughter, Rebecca, and her husband, Marshall Nash, died in a plane crash, leaving three children.

Roberts used the accident -- critics said in a calculating way -- in announcing plans for the City of Faith, his vision for a hospital, clinic and diagnostic and medical research centers that would merge medicine and prayer.

He struggled to raise money for the complex, which opened while still under construction in 1982 and was completed six years later. By that time, according to some estimates, its original price tag had doubled to $400 million and operating costs were high.

During one stretch in 1980 when funds were scarce, Roberts told donors about a vision he had while looking at the construction site.

"I felt an overwhelming holy presence all around me," Roberts recalled. "When I opened my eyes, there He stood some 900 feet tall, looking at me. There I was face-to-face with Jesus Christ, the Son of the Living God."

Posters promptly popped up in Tulsa showing a traffic sign that read, "900 ft. Jesus Xing." Columnists, political cartoonists and comics all poked fun at Roberts' vision. Even many Christians expressed embarrassment or outrage.

The same year the City of Faith opened, Roberts' oldest son, Ronnie, committed suicide after battling drugs and alcohol. Two years later, a grandson named for Roberts died shortly after birth, despite the minister's bedside prayers.

He had other problems during this time as well.

In 1979, a former employee wrote a tell-all book -- "Give Me That Old-Time Religion" -- about, among other things, the preacher's expensive personal tastes: Italian suits, diamond rings, a private jet, luxury homes, fancy cars, country club memberships.

In 1983, former daughter-in-law Patti Roberts published a book in which she spoke of "huge amounts of money" made available to her and her former husband Richard through the ministry.

At the same time, those close to Oral Roberts saw something else: the mellowing of a hard-driving man.

"He has known suffering in a very, very deep dimension," longtime friend Charles Farah told biographer Harrell. "There is something to the suffering of a human being that purifies him."

Despite negative publicity and declining TV ratings, by the mid-1980s Roberts' organization was raising more than $100 million annually and employing 2,300 people.

However, he still struggled to cover his ministry's huge expenses, and in 1987, he made his "God will call me home" fund-raising plea to raise $8 million for medical school scholarships at the university. The dental school was closed in 1987, and two years later the medical school and City of Faith medical center complex were shuttered. Although his ministries were not implicated, the televangelist scandals of the 1980s also hurt Roberts' organization.

After his 1992 heart attack, he turned over the presidency of the university to his son Richard. But Richard Roberts resigned in 2007 amid allegations that he had spent university money on personal expenses at a time when the school was deeply in debt.

The elder Roberts continued to speak at charismatic churches and appear on televangelists' programs, especially those of fellow faith healer Benny Hinn.

It was a quiet coda to a life that had unfolded in front of millions.

"All of Oral Roberts' life was controlled by two primal drives -- a relentless restlessness and a sense of divine calling," wrote biographer Harrell. "They were perhaps the same drive in secular and religious versions."

Roberts is survived by his son,Richard; his daughter, Roberta Potts of Tulsa; 12 grandchildren; and several great-grandchildren.

The funeral will be private, with plans for a public memorial service pending. His family requests donations to the Oral Roberts Ministry Healing Missions Fund, P.O. 2187, Tulsa, OK 74102, or online at www.oralroberts.com.